Method of making the seal in a panel device having a seal enclosing an electrode array

ABSTRACT

A panel device includes a plurality of plates which are sealed together hermetically with an array of electrodes disposed in the seal and seated on one of the plates as a support therefor. An effective seal between the parts is made by providing a quantity of sealing material in the seal area, moving the electrodes away from and back to the plate on which they are seated to suck the sealing material under the electrodes and to seat the sealing material on adjacent parts beneath and adjacent to the electrodes, and then passing a thin blade through the sealing material between the electrodes and the support plate in the seal area, in contact with both said parts, to cause the sealing material to wet such surface, whereby a tight leak-free hermetic seal can be formed.

United States Patent [191 Caras METHOD OF MAKING THE SEAL IN A PANELDEVICE HAVING A SEAL ENCLOSING AN ELECTRODE ARRAY [75] Inventor:

[73] Assignee: Burroughs Corporation, Detroit,

Mich.

{22] Filed: Sept. 16, I974 [21] Appl. No.: 506,227

Bernard Caras, Princeton, NJ.

[52] US. Cl. 29/25.13; 65/59; 156/736;

156/89 [51] Int. Cl. HOIJ 9/18 [58] Field of Search 29/25.l, 25.11,25.13,

[ Aug. 26, 1975 11/1974 Kuchinsky et a1. 313/220 l/l975 Bcrkenblit 65/59[57] ABSTRACT A panel device includes a plurality of plates which aresealed together hermetically with an array of electrodes disposed in theseal and seated on one of the plates as a support therefor. An effectiveseal between the parts is made by providing a quantity of sealingmaterial in the sea] area, moving the electrodes away from and back tothe plate on which they are seated to suck the sealing material underthe electrodes and to seat the sealing material on adjacent partsbeneath and adjacent to the electrodes, and then passing a thin bladethrough the sealing material between the electrodes and the supportplate in the seal area, in contact with both said parts, to cause thesealing material to wet such surface, whereby a tight leak-free hermeticseal can be formed.

6 Claims, 8 Drawing Figures PATENTED AUBZB I975 3, 9 O0 9.3 5

S'ziZET 1 [IF 2 jllllllllllllllllIIIIIIIIIIIIII IIIIIIlllllllllll I Fig.2

Fig.3

PATENTED AUBZ 6 I975 Fig.4 i; 100

Fig.5

52 F i g. 6 W

METHOD OF MAKING THE SEAL IN A PANEL DEVICE HAVING A SEAL ENCLOSING ANELECTRODE ARRAY BACKGROUND OF THE INVENTION The principles of theinvention are applicable to many types of devices; however, it isparticularly useful in the manufacture of display panels known as SELF-SCAN panels which are manufactured by Burroughs Corporation. Thesepanels include a base plate, an apextured center plate known as a cellsheet, and a face plate, and a plurality of electrode arrays disposedbetween the plates, including an array of strip cathode electrodesdisposed between the base plate and the cell sheet and seated on thebase plate. A sealing material comprising a glass frit in a suitablebinder is disposed along adjacent edges of the plates, enclosing thestrip electrodes, and the assembly is processed so that the sealingmaterial forms an hermetic seal between the various parts. Panels ofthis type have been made in this way for many years, and, in general,they have been made successfully; however, at times, leaks appear in theseals of some such panels for unknown reasons, and elimination of suchleaks is economically desirable.

SUMMARY OF THE INVENTION Briefly, the invention comprises assembling aplurality of plates and their associated electrode arrays, disposing aquantity of sealing material around the perimeter of the panel,mechanically agitating one or more electrode arrays to cause the sealingmaterial to seat on the associated plate under the electrodes, andpassing a thin blade between the electrodes and the plate thereunder toinsure wetting thereof by the sealing material.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a display panelmade according to the invention showing portions thereof;

FIG. 2 is a side elevational view of a display panel embodying theinvention;

FIG. 3 is an end elevational view of the panel of FIG.

FIG. 4 is a side elevational view of a portion of the panel of FIG. 1 atone stage in its manufacture;

FIG. 5 is a side elevational view of a portion of the panel of FIG. 1 ata second stage in its manufacture;

FIG. 6 is a side elevational view of a portion of the panel of FIG. 1 ata third stage in its manufacture;

FIG. 7 is a front, elevational view of the apparatus shown in FIG. 6;and

FIG. 8 is a plan view of the apparatus shown in FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The principles of the inventionare applicable to many types of devices, as will be clear to thoseskilled in the art. However, it will be described with reference to aSELF-SCAN panel of the type described in detail in U.S. Pat. No.3,821,586. Such a panel will be shown and described herein only insufficient detail to illustrate the principles of the invention.

Referring to the drawings, a SELF-SCAN panel 10 includes a glass baseplate having slots 30, in which are seated scanning anode wires 40. Anarray of parallel strip electrodes 50, operated as cathode electrodes,are seated on the base plate and are oriented transverse to the scanninganodes. The cathodes are provided with apertures 60. A second plate 70,the center plate or cell sheet of the panel, which is somewhat narrowerand shorter than the base plate 20 and which has an array of cellsdisposed in rows and columns (not shown) is seated on the base plate,and a face plate is seated thereon, with display anode wires disposedtherebetween. The display anodes are aligned with the scan ana glassfrit sealing material, such Pyroceram, is formed around the periphery ofthe panel in the space between the face plate and the base plate. Aportion of the sealing material is shown in FIG. 4. The sealing materialmay be dispensed from a hypodermic-type device or in any other suitablemanner.

Next, as shown in FIG. 5, the ends of the cathode assembly are raisedand lowered rapidly to force the sealing material to flow between thecathodes and under the cathodes onto the surface 22 of the perimeter ofthe base plate by hydraulic action. Next, as shown in FIG. 6, a knifeblade 110 or the like, having a rounded tip 114, (FIG. 8), is insertedbetween the cathodes 50 and surface 22 of the base plate, and it ispassed along the seal area, through the sealing material and in contactwith the cathodes and surface 22, in a tight fit therewith, to cause thesealing material to wet the surfaces of the electrodes and the baseplate. Under some circumstances, the operation of the knife blade aloneachieves the desired distribution of the sealing material, and the stepof raising and lowering the cathodes may be omitted.

Finally, the assembly is heated in an oven to cause the Pyroceram toform the desired hermetic seal in a manner well known to those skilledin the art. The panel is then processed to completion in known manner.

The blade performs the following functions:

1. Since Pyroceram is a thixotropic material, when the blade passesthrough the sealing material, it shears the sealing material, reducesits viscosity, and thus allows it to flow readily under gravity wherebyit wets the cathode surfaces and the glass surface 22 more intimately.

2. As the blade moves, the solvent, such as amyl acetate, which is inthe sealing material is smeared across the metal and glass surfaces,simultaneously dissolving and removing dirt, oil, or other foreignmatter on the surfaces.

3. It smears the sealing material onto the metal and glass surfaces andthus into more intimate contact therewith.

4. As the blade moves along the perimeter of the panel, its rounded tip110 (FIG. 8) pushes sealing material inwardly toward the seal area wherethe plates and electrodes overlay each other to thereby form a seal ofgreater length than might otherwise be achieved.

5. After the sealing material is deposted, and the solvent begins toevaporate, bubbles of solvent form in the body of the sealing material,and these bubbles are removed by the moving blade.

What is claimed is:

1. Method of hermetically sealing a flat panel comprising at least twoplates having an array of electrodes between them comprising spreading alayer of sealing material covering said plates and the electrodesassociated therewith in the area where the hermetic seal is to beformed, mechanically agitating said electrodes up and down to permitsealing material to flow under them, applying a shearing force to saidsealing material to cause it to wet said electrodes and said plate, andheating said sealing material to form the desired hermetic seal.

2. The method of claim 1 wherein said step of applying a shearing forceis achieved by passing a thin blade through said sealing materialbetween said electrodes and at least one of said plates on which saidelectrodes are supported.

3. The method of claim 1 wherein said sealing material comprises a glassfrit in a solvent binder.

4. The method of claim 1 wherein said sealing material comprises a glassfrit in a solvent binder of amyl acetate. I

5. Method of making a display panel and forming an hermetic seal thereincomprising preparing at least two support plates,

placing said two plates together in sandwich form,

disposing an array of parallel electrodes between said two plates andseated on one of said plates as a base plate, there being a seal areaalong the abutting perimeters of said plates through which saidelectrodes extend,

providing a quantity of a sealing material along said seal area andoverlaying said one plate and said electrodes,

mecahnically agitating said electrodes to cause sealing material to flowbetween said electrodes and said one plate,

passing a thin blade through said sealing material between saidelectrodes and said one plate to provide intimate wetting of saidsealing material with said electrodes and said plate, and

heating said seal area and said sealing material to form the desiredhermetic seal.

6. Method of making a display panel and forming an hermetic seal thereincomprising preparing a base plate and a top plate and placing themtogether in sandwich form, so that their perimeters form a seal area,

said base plate having an edge portion projecting beyond the adjacentedge of said top plate along said seal area,

disposing an array of parallel strip electrodes between said two platesand seated on said base plate and on the edge portion thereof,

providing a quantity of a sealing material along said sea] area,

mechanically agitating said electrodes to cause said sealing material toflow under said electrodes and fill the space between said electrodesand said base plate, and

passing a thin blade through said sealing material between saidelectrodes and said one plate to reduce the viscosity of said materialand thus provide intimate wetting of said sealing material with saidelectrodes and said plate.

1. METHOD OF HERMETICALLY SEALING A FLAT PANEL COMPRISING AT LEAST TWOPLATES HAVING AN ARRAY OF ELECTRODES BETWEEN THEM COMPRISING SPREADING ALAYER OF SEALING MATERIAL COVERING SAID PLATES AND THE ELECTRODESASSOCIATED THEREWITH IN THE AREA WHERE THE HERMETIC SEAL IS TO BEFORMED, MECHANICALLY AGITATING SAID ELECTRODES UP AND DOWN TO PERMITSEALING MATERIAL TO FLOW UNDER THEM, APPLYING A SHEARING FORCE TO SAIDSEALING MATERIAL TO CAUSE IT TO WET SAID ELECTRODES AND SAID PLATE, ANDHEATING SAID SEALING MATERIAL TO FORM THE DESIRED HERMETIC SEAL.
 2. Themethod of claim 1 wherein said step of applying a shearing force isachieved by passing a thin blade through said sealing material betweensaid electrodes and at least one of said plates on which said electrodesare supported.
 3. The method of claim 1 wherein said sealing materialcomprises a glass frit in a solvent binder.
 4. The method of claim 1wherein said sealing material comprises a glass frit in a solvent binderof amyl acetate.
 5. Method of making a display panel and forming anhermetic seal therein comprising preparing at least two support plates,placing said two plates together in sandwich form, disposing an array ofparallel electrodes between said two plates and seated on one of saidplates as a base plate, there being a seal area along the abuttingperimeters of said plates through which said electrodes extend,providing a quantity of a sealing material along said seal area andoverlaying said one plate and said electrodes, mecahnically agitatingsaid electrodes to cause sealing material to flow between saidelectrodes and said one plate, passing a thin blade through said sealingmaterial between said electrodes and said one plate to provide intimatewetting of said sealing material with said electrodes and said plate,and heating said seal area and said sealing material to form the desiredhermetic seal.
 6. Method of making a display panel and forming anhermetic seal therein comprising preparing a base plate and a top plateand placing them together in sandwich form, so that their perimetersform a seal area, said base plate having an edge portion projectingbeyond the adjacent edge of said top plate along said seal area,disposing an array of parallel strip electrodes between said two platesand seated on said base plate and on the edge portion thereof, providinga quantity of a sealing material along said seal area, mechanicallyagitating said electrodes to cause said sealing material to flow undersaid electrodes and fill the space between said electrodes and said baseplate, and passing a thin blade through said sealing material betweensaid electrodes and said one plate to reduce the viscosity of saidmaterial and thus provide intimate wetting of said sealing material withsaid electrodes and said plate.